ETC Environmental Monitoring & Instrumentation 2

Question 1

A field technician uses a combustible gas indicator (CGI) and observes a reading of 10% LEL in a utility vault. What action should be taken?

Accepted Answer

Ventilate the space and continue monitoring before entry

Answer

A 10% LEL reading indicates a measurable combustible gas presence; standard practice requires forced ventilation and continued monitoring to trend whether concentrations are rising or falling before permitting entry.

Question 2

Which EPA method is the standard for measuring total metals in water samples using inductively coupled plasma mass spectrometry (ICP-MS)?

Accepted Answer

EPA Method 200.8

Answer

EPA Method 200.8 is the standard aqueous method for determining trace elements in water by ICP-MS, providing low detection limits for metals like arsenic, lead, and mercury.

Question 3

What is the significance of measuring oxidation-reduction potential (ORP) in a groundwater sample during field monitoring?

Accepted Answer

ORP characterizes the redox environment, which determines which contaminant degradation pathways are occurring

Answer

ORP (measured in millivolts) indicates whether subsurface conditions are oxidizing or reducing, which directly controls natural attenuation processes such as aerobic biodegradation, sulfate reduction, or methanogenesis.

Question 4

When collecting a low-flow groundwater sample, what field parameter stability criteria typically indicates the sample is representative of aquifer conditions?

Accepted Answer

Three successive readings of pH within ±0.1 unit, conductance within ±3%, DO within ±0.3 mg/L, and ORP within ±10 mV

Answer

Low-flow sampling protocols require stabilization of pH (±0.1), specific conductance (±3%), dissolved oxygen (±0.3 mg/L), and ORP (±10 mV) across at least three consecutive readings before sample collection.

Question 5

A technician uses an XRF (X-ray fluorescence) analyzer on soil at a brownfield site. What primary advantage does XRF offer compared to laboratory analysis?

Accepted Answer

XRF gives real-time, non-destructive elemental analysis enabling rapid site-wide screening

Answer

Portable XRF provides immediate, non-destructive elemental (metals) analysis in the field, allowing technicians to screen hundreds of locations per day and guide confirmatory sampling without waiting for laboratory turnaround.

ETC - Environmental Technician Certification Practice Test

ETC - Environmental Technician Certification Practice Test

ETC Environmental Monitoring & Instrumentation 2